Shiguan migmatite of Yuexi County is part of former North Dabie Complex. The zircon SHRIMP U-Pb dating shows: the first metamorphism occurred at 232 Ma, equivalent to early period of Late Triassic, and the second metamorphic at 207 Ma, equivalent to late period of Late Triassic. Magmatic detrital zircons with well developed rhythmic zoning constitutes the core of the composite zircon and have the ages of ages of 560, 444, 394, 378 and 331 Ma respectively, suggesting that protolith was not magmatic rock instead of sedimentary rock. Research also shows that the Shiguan migmatite of the North Dabie has gone through two metamorphisms: (1) ultra-high pressure metamorphism at the time of 232 Ma (n = 5, mean age) and 2) retrograde metamorphism at 207 Ma. The two ages of metamorphism are consistent with the time of ultrahigh-pressure metamorphic and retrograde metamorphism in Sulu region.

Dongyuan W deposit is a newly-found large-scale scheelite deposit, which is also the biggest one in south of Anhui province. The discovery of the Dongyuan W deposit set the direction for mineral exploration and laid groundwork for further exploration. This paper preliminarily analyzed regional structural background and metallogenic controlling factors, firstly obtained U-Pb age of zircon by using SHRIMP. The results showed that ore-forming age of the granite-porphyry in the Dongyuan porphyry W deposit is 148. 6 ±1. 8 Ma (n = 16, MSWD=1. 5), and the granite porphyry rock was product of late Jurassic magmatic movement. The results also suggested that the regional tungsten mineralization might extend from South China to the Middle and Lower Reach of the Yangtze River.

Lakes are an important component of terrestrial carbon cycling. As the trend of eutrophication in many lakes continues, the mechanisms of organic carbon (OC) burial remain unclear. This paper aims to understand the distribution of OC and the effect of trophic level changes on OC burial in Chaohu Lake, a shallow eutrophic lake located in the lower reaches of the Yangtze River, SE China. Two hundred and one surface sediment samples (0-20cm) and 53 subsurface samples (150-200cm) from the lake were collected. The OC accumulation rates (OCARs) are relatively low, with an average of 10.01g/m(2)/year in the surface sediments. The spatial distribution of the OCARs is similar to that of allochthonous OC. The difference in total phosphate (TP) content between the surface and subsurface sediments (TP) is significantly correlated with the autochthonous OC, suggesting that TP loading is a critical limiting nutrient for the lakes primary productivity. It is concluded that allochthonous OC is the dominant source of total OC in surface sediments compared to autochthonous OC. The primary productivity of Lake Chaohu increased due to increasing nutrient loading. However, the autochthonous OC contributed 11% of the total OC in the surface sediments. This could be ascribed to strong mineralization in the water column or surface sediments.